Title : VISCOUS AND INVISCID STAGNATION FLOW IN A DISSOCIATED HYPERVELOCITY FREE STREAM

Corporate Author : DEPUTY COMMANDER AEROSPACE SYSTEMS INGLEWOOD CALIF

Personal Author(s) : INGER,G.R.

Report Date : 15 JUL 1962

Pagination or Media Count : 1

Abstract : The effects of nonequilibrium free stream dissociation on hypersonic stagnation flow over a blunt-nosed body are analyzed and compared to the similar flow in an initially undissociated ambient gas. The theory is primarily concerned with the case of high Reynolds number flows in which a thin, highly-cooled boundary layer and equilibrium inviscid flow exist. Significant changes in the bow shock geometry, stagnation gas state, and nonequilibrium heat transfer are found when the free stream dissociation involves more than 10% of the total energy. It is observed that for large amounts of both atomic O and N ahead of the body, the equilibrium shock layer properties converge toward those pertaining to chemically and vibrationally-frozen flow across the bow shock. Moreover, under certain conditions, the equilibrium ionization and radiant heat transfer can be increased by an order of magnitude, and the usual reduction in frozen boundary layer heat transfer due to a highly-cooled non-catalytic surface can increase two-fold. Low Reynolds number effects, including nonequilibrium relaxation behind the bow shock, are examined. Free stream dissociation can substantially enhance the freezing of the shock layer while simultaneously delaying the onset of vorticity interaction and viscous layer effects. (Author)